Kikyo was the shinto preistess entrusted by the Yokai Taijiya(Demon Slayers) to guard and purify the fabled Jewel of the Four Souls (Shikon no Tama).

Kikyo slew many yokai that tried to gain possession of the jewel; however, she could not force herself to kill Inuyasha, a han'yo who is half-human and half-Inu yokai/Dog Demon. She felt as though InuYasha was idled from his kind, as she was with hers. On several occasions she would immoblize Inuyasha when he attempted to steal the jewel, and had brief conversations with him. Inuyasha had followed her for a long period of time. Soon they spent more time together, and the two of them began to have feelings of love and compassion for each other. Kikyo told Inuyasha that the Shikon Jewel could be used to make him completely human, as opposed to his original intention of becoming a full yokai. Kikyo speculated that if the jewel were used to turn Inuyasha into a human, it would be purified and vanish, which would free Kikyo from her duty to protect the jewel and she could then live as a normal woman with Inuyasha. He agreed, believing this was the better option.

The following day, Kikyo arrived at the area where they had agreed to meet, but Inuyasha was not present. When she went out into a field to attempt to find him, she was attacked by Naraku, disguised as Inuyasha. She collapsed to the ground as he escaped with the jewel, proclaiming that he had "absolutely no intention of becoming human" and that the jewel needed to "absorb even more bitter blood", thus effectively framing Inuyasha for the evil deed. Kikyo limped back to the village in pain, only to find that the real Inuyasha, who was also tricked by Naraku in thinking that Kikyo wanted to kill him, had attacked the village and was escaping with the Shikon jewel.

Drawing on her last strength, Kikyo fired a sealing arrow (F¨ħin no Ya) at Inuyasha to seal him to the Sacred Time Tree (Goshinboku). She collapsed the instant after Inuyasha was sealed, and instructed her younger sister Kaede to burn the Shikon no Tama with her body to assure that none can exploit the terrible powers the jewel holds. With that, she died. In the anime (but not in the manga), this tragic fate of Kikyou was foretold through a curse laid by Tsubaki, (a powerful Miko) when she told Kikyo that "a priestess must abandon her heart to achieve power ... this includes love as well" and "You must extinguish love. You must never hold a man dear," or else she would "suffer an untimely death."

Re-incarnation in Kagome
In present day Tokyo, the Higurashi family now resides in a shrine compound that houses the Tree of Ages and the ancient well. Kagome Higurashi, a Jr. High-school student who just turned 15, has to retrieve their family cat Buyo from the well. She was ready to leave the well with the cat when a centipede yokai Mistress Centipede (Mukade Joro) emerged from the well, dragging a very confused Kagome through the time slip and back to the Sengoku period (Feudal Era of Japan) approximately 500 years ago.

Kagome was proven to be Kikyo's reincarnation, not only from her distinct resemblance to Kikyo (far more evident in the manga; the character designer for the anime chose to make Kikyo and Kagome different in appearance in order to emphasize they are not the same person), when the Shikon no Tama was revealed to be concealed within her body, due to the fact that Kikyo was burned with the jewel after she died, and the fact she was able to release Inuyasha from the arrow Kikyo used to bind InuYasha to the Tree of Ages.

It has been seen more than once Kagome is not an ordinary reincarnation. She possesses an unusually strong soul, which proved to be too much for Kanna's mirror to contain. Furthermore, Kagome was able to part with a portion of her soul so that Kikyo could be sustained in the world of the living. Kagome's actions have often unwittingly echoed that of Kikyo's in the past, and she has often been called upon to perform tasks that Kikyo herself can only instruct Inuyasha or Kagome in performing.

After Resurrection
Kikyo had been dead for fifty years already until the yokai Kijo Urasue attacked her village and stole Kikyo's ashes along with some burial soil from her grave. Using her powerful magic, she re-created Kikyo's body in the hopes that Kikyo would find and retrieve the shards of the Shikon Jewel (which was incidentally shattered by Kagome) but, to the old yokai's dismay, Kikyo's soul had not returned to her body.

Angered for a while, until Kagome and Inuyasha, along with Shippo and Kaede, were attacked by Urasue's guards. With a quick attack, the yokai had Kikyo's reincarnated soul and eventually (with Inuyasha's unknowing help) revived Kikyo, who immediately killed Urasue and went on to attack Inuyasha. Kagome however somehow managed to get most of her soul back after Kikyo's assault. With only one part of soul within her Kikyo fled, fueled by the bitter hatred she felt for Inuyasha at the moment of her death.

However, despite this hatred that she bears for him, she cannot deny her feelings of love and well being for him as well, for it is her wish to die with him and descend into hell, where they can be together forever. Kikyo attempted to do this once, yet upon remembering Kagome, Inuyasha interrupted the process.

Kikyo's body is not made of flesh and blood; she only has a bit of soul and strong, willful determination. As a result of this, she must find ways to sustain her "unlife" until she can kill Naraku. Kikyo fulfills this need by using Shinidamachu (dead soul insects, known as Soul Collectors in the dub of the anime) to collect the souls of deceased women, allowing her to move and continue her journey.

It is important to note that the Kikyo appearing after her death is very different from the one who had just died. She no longer smiles and hardly shows any emotion except pain or panic when being attacked by an opponent. She killed a priest who was trying to save her soul by releasing her from her desire to live, thus ending her life. However, this changes as the story progresses and Kikyo adapts more and more to her undead existence. A lot of this change can be attributed to the different characters she meets along the way.

Whenever she is not going after Naraku, she can be seen aiding the wounds of soldiers.

Travelling with Kohaku
Naraku stated how the shard in Kohaku's back radiated such "dreadful purity" and if that shard were taken and combined with the nearly completed Shikon jewel, then both Naraku and the Shikon Jewel would be purified at once. It is for this reason that Naraku returned to Mount Hakurei to reclaim his negative heart as a countermeasure to Kikyo's plan.

Naraku uses his human heart's power to send webs after Kikyo that would corrupt her. Kikyo was eventually overpowered by Naraku's malice and, to protect Kohaku, she sent him away with Asuka and Kocho; however, they were easily dispatched as their powers proved useless against Byakuya. Sesshoumaru interferes, however, and Byakuya is unable to capture Kohaku.

When Inuyasha and Kagome arrive, she discovers Naraku has also corrupted Kagome with his webs in order to render them both unable to purify the Shikon Jewel and Kagome unable to purify Kikyo, as the girl had been able to do in the past. To rectify this, she sends Kagome to recover a sacred bow from Mt. Asuza that can be used to purify her shouki wound, but while Kagome and InuYasha are gone, Naraku reappears and captures Kikyo along with Koga, Miroku, Sango, Shippou and Kirara. However, Kikyo notices that the Shikon shards in Koga's legs were purified as part of Midoriko's will, meaning that she could use his shards to purify the Shikon Jewel just as she had attempted to do so with Kohaku's shard.

Final Moments
At the end of chapter 462, Kagome is shocked to find that the Jewel is now inside of Kikyo's body. In chapter 463, with the help of Kagome's sacred arrow, Kikyo purifies the Shikon Jewel, and fires the arrow out of her body and at Naraku. His shouki is only able to corrupt half of the Jewel, and Kikyo's spiritual power and Naraku's jyaki begin to battle within the jewel.

However, Naraku's darkness proves too powerful and overcomes Kikyo's power, completely corrupting the Jewel. Seeing that her life is practically over, Kikyo weakly tells Kagome that the rest is up to her, and that the bow from Mt. Asuza now belongs to Kagome. Shocked, Kagome asks what Kikyo means, but before the miko can continue, Naraku claims that Kikyo has lost to his jyaki and he strikes out at her with one of his tentacles. Inuyasha slashes through it before it reaches Kikyo and Kagome, but Naraku merely laughs and tells Inuyasha that he'll need to start thinking of how to defeat him without Kikyo, and leaves.

Sesshoumaru, in an overgrown field with Kohaku and Rin, comments that the scent on the wind has changed, and that it is too late. Kaede also notices some sort of change, noting that the sunset is the color of blood.

With Naraku gone, a crushed Inuyasha holds the dying Kikyo in his arms. Inuyasha then asks the others to leave them in private. Before leaving, Kagome has her face in her hands, attempting to hide her tears as she laments over being unable to save Kikyo. In thought, Kikyo wishes for Kagome not to cry, for she feels her soul has finally been saved.

Alone together, Kikyo tells Inuyasha of how she wished to become an ordinary woman when the Shikon Jewel vanished. Inuyasha tells her that ever since he was born, Kikyo was his first love. His tears splatter on Kikyo's cheek, and she comments that this is the first time she's seen him make such a face and cry.

At that, Inuyasha cries that he was unable to save her. But Kikyo continues to smile at him, saying that he came for her and that was good enough. He then looks at her smiling face tearfully, and it's her first real smile in a long while. After Inuyasha kisses Kikyo goodbye, Kikyo calls his name in her thoughts as she looks at him with tear-filled eyes.

Finally in peace, Kikyo dies and disappears into a bright cluster of souls and light, which the Shinidamachu whirl around as it glows among the group. Shippo says that it looks as if her soul is bidding farewell to them all, and Kagome notices how warm it is. The Shinidamachu then carry Kikyo's soul into the sky.

Inuyasha is mournful as he looks into the sky, but says that Kikyo will not suffer anymore, and that her soul doesn't want them to mourn. Kikyo's last departing words are a promise that she'll always protect Inuyasha.

In Chapter 475 Naraku reveals that ever since Kikyo's death the core of his near-complete Shikon Jewel has had a purified core that he has been unable to corrupt. This has lead to speculation that Kikyo may have somehow injected at least part of her soul into the Jewel.